Search for: All records

During International Ocean Discovery Program (IODP)/Inter- national Continental Drilling Project (ICDP) Expedition 364, the peak ring of the Chicxulub impact crater was drilled in April–May 2016. The expedition recovered 829 m of core, from 505.7 to 1334.7 meters below seafloor (mbsf). Because the geographic in situ orien- tation of the core is not preserved during the drilling process, we report orientation corrections for all core sections. Angular correc- tion values were determined by comparing and matching fractures and lithologic contacts between computed tomography scans of the cores and downhole acoustic borehole images as well as comparing fractures and contacts from one core section to another. The orien- tation correction values can be used to reorient cores to true geo- graphic north, enabling proper assessment of directionality for structural deformation, paleomagnetic indicators, and sedimentary transport data with the Expedition 364 cores. 

The ~180-km-diameter Chicxulub peak-ring crater and ~240-km multiring basin, produced by the impact that terminated the Cretaceous, is the largest remaining intact impact basin on Earth. International Ocean Discovery Program (IODP) and International Continental Scientific Drilling Program (ICDP) Expedition 364 drilled to a depth of 1335 m below the sea floor into the peak ring, providing a unique opportunity to study the thermal and chemical modification of Earth’s crust caused by the impact. The recovered core shows the crater hosted a spatially extensive hydrothermal system that chemically and mineralogically modified ~1.4 × 10 5 km 3 of Earth’s crust, a volume more than nine times that of the Yellowstone Caldera system. Initially, high temperatures of 300° to 400°C and an independent geomagnetic polarity clock indicate the hydrothermal system was long lived, in excess of 10 6 years.